(2S,4S)-4-acetylthio-N-allyloxycarbonyl-2-[(E)-3-allyloxycarbonylamino-1-propenyl]-N-allyloxycarbonylpyrrolidine

(2S,4R)-2-((E)-3-Allyloxycarbonylamino-propenyl)-4-methanesulfonyloxy-pyrrolidine-1-carboxylic acid allyl ester

(2S,4R)-2-[(E)-3-allyloxycarbonylamino-1-propenyl]-N-t-butoxycarbonyl-4-t-butyldimethylsilyloxypyrrolidine